5. The Hoover Dam
When I first visited The Hoover Dam in my early twenties, fresh out of college and full of the curiosity of a new engineer, I never would have imagined the impact the grandeur of this monument would have on my professional life. This is not because at the time, Hoover Dam was the most impressive structure I had ever been on, but rather it is the story of how the structure came into existence and how it conquered once thought to be impossible obstacles.
To create the Hoover Dam the contractors had to divert the flow of the mighty Colorado River through tunnels dug inside the canyon walls. The tunnels were 56 feet in diameter with a combined length was nearly 16,000 feet. Following the diversion, engineers had to construct a structure tall and strong enough to sustain future generations and keep the Colorado river under control. As shown in the video, the construction of the Hoover Dam necessitated the use of previously unused design practices.
When the Hoover Dam was completed in 1935, it was the world’s largest concrete structure and the largest electric producing facility. Years later as I stood 736 feet above the river bed, I felt the power of the structure. What inspired me at that instant was the humbling realization that at one point, this structure was just an idea.
Video – The story of the Hoover Dam
4. Boston Big Dig
Recognized as the largest, most complex, and technologically challenging highway project in the history of the United States, the Central Artery/Tunnel Project significantly reduced traffic congestion and improved mobility in one of America’s oldest and most congested major cities. In addition, it helped improve the environment, and established the groundwork for continued economic growth for Massachusetts and all of New England.
The project, which replaced Boston’s deteriorating six-lane elevated Central Artery (I-93) with an underground highway, two new bridges over the Charles River, extended I-90 to Boston’s Logan International Airport, and Route 1A, created more than 300 acres of open land and reconnected downtown Boston to the waterfront.
3. Transcontinental Railroad
By the middle of the 19th century, the benefits brought by the host of advances of the industrial age were gradually beginning to reach America. These advances coupled with the desire to connect East and West prompted the spectacular engineering project that forever changed the continent. Those building the railroad battled against hostile terrain, a civil war and the Wild West. This video provides an interesting narrative on the construction of the Transcontinental Railroad and the social-economic conditions of the time.
2. The Great Wall of China
The Great Wall of China is the longest man-made structure in the world at about 4,160 miles long. The wall was constructed between the 5th Century BC and the 16th Century BC. What is most impressive about this structure is the fact that it was accomplished without the use of modern machinery in extremely rough terrain.
1. Pyramids of Giza, Egypt
Rising out of the sand on the outskirts of Cairo are the Pyramids of Giza, ancient monuments that are the last standing of the Seven Wonders of the Ancient World. The ancient necropolis consists of the Pyramid of Khufu, the Pyramid of Khafre, the Pyramid of Menkaure, and the Great Sphinx.
The allure of the pyramids is undeniable, with archaeologists still fascinated by their construction. While some think the stones were dragged from a quarry and somehow lifted into place, others think that the stones were built in place with some kind of limestone concrete. Whatever the mode of construction, this project qualifies as the most impressive given the size and the mystery behind its impeccable construction.
Video – Building the great pyramid